System and method for designing scleral lenses

ABSTRACT

A system and method for designing scleral lenses includes a computer, a camera and a lathe connected by a network. The camera captures a set of sagittal images at each of a set of sagittal planes of an eye. A combined sagittal image is created from each set of sagittal images. A spline curve is defined for each combined sagittal image creating a set of spline curves. A set of back surface curves is created from the set of spline curves. A back lens surface is generated from the set of surface curves. A front lens surface is generated adjacent the back lens surface. A point cloud is generated from the back lens surface and the front lens surface. The point cloud is converted to a lens image. The lens is converted to a text file for use by the lathe to cut the scleral lens.

FIELD OF THE INVENTION

The present invention relates to optical systems. In particular, thepresent invention relates to systems and methods for designing sclerallenses.

BACKGROUND OF THE INVENTION

Keratoconus is a degenerative disorder of the eye in which structuralchanges within the cornea cause thinning and loss of curvature.Keratoconus can cause substantial distortion of vision, including doublevision (diplopia), streaking and hyper-sensitivity to light. Keratoconusis typically diagnosed during adolescence. Debilitating deterioration invision can occur.

Refractive surgical procedures, such as Laser-Assisted Keratomileusis(“LASIK”), are often prescribed to correct common vision disorders. Ingeneral, the LASIK procedure is performed by making a thin flap ofcorneal tissue, folding the flap out of the way, altering the shape ofthe cornea by subtracting tissue using an excimer laser, then replacingthe flap.

Despite the many advantages of LASIK, severe side effects can occur. Forexample, halos, starbursts, loss of low-light sensitivity and drynessare common side effects of the procedure. In other less common sideeffects, the flap may fail to adhere properly to the eye's surface ormay cause microscopic wrinkles in the flap called corneal striae.Studies indicate that flap complications occur in from 0.3 to 5.7percent of LASIK procedures, according to the April 2006 issue ofAmerican Journal of Ophthalmology. These flap complications can lead toan irregularly shaped eye surface and distorted vision.

Irregular astigmatism also may occur from LASIK correction that is notcentered properly on the eye or from irregular healing after theprocedure.

In another side effect, epithelial ingrowth occurs when cells from theouter layer of the cornea, the epithelium, grow under the flap. In somecases, blurred vision and or chronic discomfort can result.

In yet another side effect, diffuse lamellar keratitis (“DLK”),nicknamed “Sands of the Sahara,” results in which an inflammation underthe LASIK flap occurs. But if the inflammation is uncontrolled, as inDLK, it can interfere with healing and cause vision loss.

The prior art has provided different methods to compensate for the sideeffects of LASIK surgery; however, none is completely satisfactory. Forexample, corneal implants, called “Intacs,” may be prescribed to holdthe cornea in place.

Another remedy for LASIK side effects is gas permeable contact lenses,such as scleral lenses, which are prescribed as a cost effective andsafe remedy. However, the prior art methods to design and constructsclera lenses, so far, have been ineffective to produce an adequate“fit” at an economical price, so that the remedy cannot be widelyprescribed or used.

For example, U.S. Pat. No. 5,570,142 to Lieberman discloses a contactlens for asymmetric aspheric corneas with a peripheral portion to fitperipheral portion of the cornea as determined by scan of subject eye.The contact lens is not substantially greater in diameter than thecornea. The process for manufacturing the lens uses three-dimensionaltopographic data from points on the cornea. The data is used to shape atleast the peripheral portion of the posterior surface of the lens.However, the process in Lieberman limited to corneal lenses only and notsuitable for scleral lenses.

U.S. Pat. No. 5,452,031 to Ducharme discloses a method for manufacturinga contact lens. The contact lens is made through use of a computerimplementing an approximation of the cornea. Piecewise polynomialsapproximating the corneal topology have equal first and secondderivatives where they join. A polynomial representing the centraloptical portion of the lens and the piecewise polynomial adjacent to thecentral optical portion curve have an equal first derivative where theyjoin. A contact lens is cut corresponding to the lens surface defined bythe piecewise polynomials. However, the method in Ducharme requires anapproximation of only the cornea thereby leading to an inaccuraterepresentation of the scleral surface and an uncomfortable fit.

The prior art fails to disclose or suggest a system and method fordesigning scleral lenses that conform to the shape of the eye surface.Therefore, there is a need in the art for a system and method fordesigning scleral lenses that accurately follows the shape of the eyesurface such that the lens does not rotate when worn or moveexcessively, and can be worn comfortably and safely on the eye.

SUMMARY

In a preferred embodiment, a system and method for designing sclerallenses is disclosed. The system includes a computer, a camera, and alathe connected by a network.

In a preferred embodiment, the camera captures a set of sagittal imagesat each of a set of sagittal planes of an eye and sends the set ofsagittal images to the computer. A combined sagittal image is created ateach sagittal plane from each set of sagittal images. A spline curve isdefined for each combined sagittal image to create a set of splinecurves. A set of back surface curves is created from the set of splinecurves. A back optical surface is generated. A back haptic surface curveis created for each back surface curve creating a set of back hapticsurface curves. A back haptic surface is generated from the set of backhaptic surface curves. A blend surface is generated to connect the backhaptic surface to the back optical surface to create the back lenssurface. The process is repeated to create the front lens surface.

A font surface curve is created at each plane adjacent to the backsurface to create a set of front surface curves. A front optical surfaceis generated. A front haptic surface curve is created for each frontsurface curve creating a set of front haptic surface curves. A fronthaptic surface is generated from the set of front haptic surface curves.A blend surface is generated to connect the front haptic surface to thefront optical surface to create the front lens surface.

A “point cloud” is generated from the back lens surface and the frontlens surface. The point cloud is converted to a lens image. The lens isconverted to a text file. The text file is sent to the lathe and ascleral lens is cut by the lathe using the text file.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed embodiments will be described with reference to theaccompanying drawings.

FIG. 1 is a schematic for a system for designing a scleral lens of apreferred embodiment.

FIG. 2 is a flowchart of a method for designing a scleral lens of apreferred embodiment.

FIG. 3A is a set of sagittal planes of an eye of a preferred embodiment.

FIG. 3B is a sagittal image captured on a sagittal plane of a preferredembodiment.

FIG. 3C is a sagittal image taken on a sagittal plane of a preferredembodiment.

FIG. 3D is a combined sagittal image of a preferred embodiment.

FIG. 4 is a spline curve on a corneal surface of a sagittal image of apreferred embodiment.

FIG. 5 is a near point curve on a sagittal image of a preferredembodiment.

FIG. 6 is a set of near point curves of a preferred embodiment.

FIG. 7A is a point cloud of an optical section of a preferredembodiment.

FIG. 7B is a set of back surface points of a preferred embodiment.

FIG. 7C is a point cloud of an optical section and an optical surface ofa preferred embodiment.

FIG. 7D is an optical surface and a trim tool of a preferred embodiment.

FIG. 7E is an optical surface of a preferred embodiment.

FIG. 8 is a drawing of an optical back surface trimmed to a near pointcurve of a preferred embodiment.

FIG. 9 is a drawing of an optical back surface section and a hapticsurface section of a preferred embodiment.

FIG. 10 is a drawing of a back surface of a lens of a preferredembodiment.

FIG. 11 is a drawing of a back surface of a lens, a spline of a frontsurface of a lens, and a front optical section of a preferredembodiment.

FIG. 12 is a drawing of a front surface and a back surface of a lens.

FIG. 13 is a drawing of a point cloud of a lens.

FIG. 14 is a drawing of a completed lens.

DETAILED DESCRIPTION

It will be appreciated by those skilled in the art that aspects of thepresent disclosure may be illustrated and described herein in any of anumber of patentable classes or context including any new and usefulprocess, machine, manufacture, or composition of matter, or any new anduseful improvement thereof. Therefore, aspects of the present disclosuremay be implemented entirely in hardware, entirely in software (includingfirmware, resident software, micro-code, etc.) or combining software andhardware implementation that may all generally be referred to herein asa “circuit,” “module,” “component,” or “system.” Further, aspects of thepresent disclosure may take the form of a computer program productembodied in one or more computer readable media having computer readableprogram code embodied thereon.

Any combination of one or more computer readable media may be utilized.The computer readable media may be a computer readable signal medium ora computer readable storage medium. For example, a computer readablestorage medium may be, but not limited to, an electronic, magnetic,optical, electromagnetic, or semiconductor system, apparatus, or device,or any suitable combination of the foregoing. More specific examples ofthe computer readable storage medium would include, but are not limitedto: a portable computer diskette, a hard disk, a random access memory(“RAM”), a read-only memory (“ROM”), an erasable programmable read-onlymemory (“EPROM” or Flash memory), an appropriate optical fiber with arepeater, a portable compact disc read-only memory (“CD-ROM”), anoptical storage device, a magnetic storage device, or any suitablecombination of the foregoing. Thus, a computer readable storage mediummay be any tangible medium that can contain, or store a program for useby or in connection with an instruction execution system, apparatus, ordevice.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. The propagated data signal maytake any of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device. Program codeembodied on a computer readable signal medium may be transmitted usingany appropriate medium, including but not limited to wireless, wireline,optical fiber cable, RF, or any suitable combination thereof.

Computer program code for carrying out operations for aspects of thepresent disclosure may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, C++, C#, .NET, Objective C, Ruby, Python SQL, or othermodern and commercially available programming languages.

Aspects of the present disclosure are described with reference toflowchart illustrations and/or block diagrams of methods, systems andcomputer program products according to embodiments of the disclosure. Itwill be understood that each block of the flowchart illustrations and/orblock diagrams, and combinations of blocks in the flowchartillustrations and/or block diagrams, can be implemented by computerprogram instructions. These computer program instructions may beprovided to a processor of a general purpose computer, special purposecomputer, or other programmable data processing apparatus to produce amachine, such that the instructions, which execute via the processor ofthe computer or other programmable instruction execution apparatus,create a mechanism for implementing the functions/acts specified in theflowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that when executed can direct a computer, otherprogrammable data processing apparatus, or other devices to function ina particular manner, such that the instructions when stored in thecomputer readable medium produce an article of manufacture includinginstructions which when executed, cause a computer to implement thefunction/act specified in the flowchart and/or block diagram block orblocks. The computer program instructions may also be loaded onto acomputer, other programmable instruction execution apparatus, or otherdevices to cause a series of operational steps to be performed on thecomputer, other programmable apparatuses or other devices to produce acomputer implemented process such that the instructions which execute onthe computer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

Referring to FIG. 1, system 100 includes computer 101, camera 102, andlathe 103, each connected to network 104. Computer 101 includesprocessor 105 and memory 106 connected to processor 105. Lens designprocess 107 is saved in memory 106 and executed by processor 105.

In use, camera 102 captures a set of sagittal images of an eye. The setof sagittal images are sent to computer 101 through network 104. A lensis designed using lens design process 107 from the set of sagittalimages, as will be further described below. The lens design is sent tolathe 103 through network 104. Lathe 103 cuts the lens according to thedesign.

In a preferred embodiment, camera 102 is a Visante® optical coherencetopography (“OCT”) unit available from Carl Zeiss Meditec, Inc. Othersuitable imaging devices known in the art may be employed.

In a preferred embodiment, lathe 103 is a DAC ALM lens lathe availablefrom DAC International, Inc. Other suitable lens lathes known in the artmay be employed.

Referring to FIG. 2, lens design process 200 will be described.

In a preferred embodiment, a back lens surface is first created thatwill rest on an eye. In this embodiment, a front lens surface is createdsecond, based on the back lens surface, as will be further describedbelow.

In step 201, a set of overlapping sagittal images is captured at each ofa set of sagittal planes of an eye.

In step 202, each set of sagittal images are combined to create acombined sagittal image for each sagittal plane.

In a preferred embodiment, each set of sagittal images are digitally“stitched” together using a graphics editing software program to createthe combined sagittal image, as will be further described below.

In another embodiment, portions of each set of sagittal images are cutand pasted together using a graphics editing software program to createthe combined sagittal image. Other image editing techniques known in theart may be employed.

In step 203, a set of back surface curves are created. A spline curve isdefined on each combined sagittal image by tracing the surface of theeye to create a set of spline curves, as will be further describedbelow. A lens curve is also generated for each combined sagittal imageby converting each spline curve to a near point curve at a predetermineddistance from the eye surface, as will be further described below.

In step 204, an optical surface is generated.

In step 205, a haptic surface curve is created for each lens curve tocreate a set of haptic surface curves.

In step 206, a haptic surface is generated from the set of hapticsurface curves.

In step 207, a blend surface is generated for the optical surface andthe haptic surface.

In step 208, the haptic surface, the blend surface, and the opticalsurface are combined to form a lens surface.

In step 209, if the front surface has been created, then lens designprocess 200 proceeds to step 211. If the front surface has not beencreated, then lens design process 200 proceeds to step 210.

In step 210, a set of front surface curves are created. In thisembodiment, a front lens curve is generated at each sagittal plane bycreating a near point curve at a predetermined distance from the backlens surface, as will be further described below.

Steps 204, 205, 206, 207, and 208 are repeated to create the front lenssurface from the set of front surface curves.

In step 211, the back lens surface and front lens surface are convertedto a point cloud.

In step 212, the point cloud is converted to a three-dimensional lensimage.

In step 213, the three-dimensional lens image is converted to a textfile. In step 214, the lens is cut by a lathe using the text file. Inthis step, the text file is a cutting pattern of the lens that guidesthe movement of the lathe.

Referring to FIG. 3A, step 201 will be further described. Eye 301 hassagittal planes 302, 303, 304, 305, 306, and 307, and reference point344. Angle α separates each of sagittal planes 302, 303, 304, 305, 306,and 307.

In the preferred embodiment, six planes are employed. In otherembodiments, other numbers of planes may be employed.

In a preferred embodiment, angle α is approximately 30°. In otherembodiments, other angles may be used.

A set of sagittal images is captured at each of sagittal planes 302,303, 304, 305, 306, and 307. At sagittal plane 302, sagittal image 308is captured from point 309 to point 310 and sagittal image 311 iscaptured from point 312 to point 313. At sagittal plane 303, sagittalimage 314 is captured from point 315 to point 316 and sagittal image 317is captured from point 318 to point 319. At sagittal plane 304, sagittalimage 320 is captured from point 321 to point 322 and sagittal image 323is captured from point 324 to point 325. At sagittal plane 305, sagittalimage 326 is captured from point 327 to point 328 and sagittal image 329is captured from point 330 to point 331. At sagittal plane 306, sagittalimage 332 is captured from point 333 to point 334 and sagittal image 335is captured from point 336 to point 337. At sagittal plane 307, sagittalimage 338 is captured from point 339 to point 340 and sagittal image 341is captured from point 342 to point 343.

In a preferred embodiment, two overlapping sagittal images are capturedat each sagittal plane. In this embodiment, the pupil of the subject eyeis dilated. A low power infrared light beam is centered on the dilatedpupil to create the reference point. The eye is moved laterally to movethe infrared radiation beam off-center to capture the two overlappingsagittal images. Other techniques known in the art may be employed.

Referring to FIGS. 3B and 3C by way of example, sagittal image 308 spansfrom point 309 to point 310. Sagittal image 308 has reference point 344,eye surface 345, and pupillary center 349. Sagittal image 311 spans frompoint 312 to point 313. Sagittal image 311 has reference point 344, eyesurface 346, and pupillary center 349.

Referring to FIG. 3D, step 202 will be further described. Combinedsagittal image 347 includes sagittal image 308 and sagittal image 311.Sagittal image 308 has eye surface 345. Sagittal image 311 has eyesurface 346. Combined sagittal image 345 has reference point 344,combined eye surface 348, and pupillary center 349. Eye surfaces 345 and346 form combined eye surface 348.

In a preferred embodiment, each of eye surfaces 345 and 346 is a“surface profile” created by surface detection in the Visante® OCT unitwhen each of sagittal images 308 and 311 is captured.

In a preferred embodiment, sagittal image 308 and 311 are combined byoverlapping eye surfaces 345 and 346 at pupillary center 349 to create a“best fit” combined eye surface. In this embodiment, sagittal images 308and 311 are digitally “stitched” together using a graphics editingsoftware.

In another embodiment, sagittal images 308 and 311 are combined byoverlapping eye surfaces 345 and 346 and aligning eye surfaces 345 and346 at reference point 344 to create a “best fit” combined eye surface.

In a preferred embodiment, combined sagittal image 347 is created bydigitally “stitching” sagittal images 308 and 311 using Adobe Photoshopsoftware available from Adobe Systems, Inc. In this embodiment, sagittalimages 308 and 311 are imported into Adobe Photoshop and combined usingthe “Photomerge” tool in Adobe Photoshop. Other suitable image editingsoftware known in the art may be employed.

In another embodiment, portions of sagittal images 308 and 311 are “cut”and “pasted” together, using Adobe Photoshop to create combined sagittalimage 347. Other image editing software and techniques known in the artmay be employed.

Referring to FIG. 4, step 203 will be further described. Combinedsagittal image 401 includes eye surface 403. Eye surface 403 has surfaceapex 405. Spline curve 402 traces eye surface 403 and intersects surfaceapex 405. Spline curve 402 has a plurality of control points 404 tomanipulate the curvature of spline curve 402.

In a preferred embodiment, spline curve 402 and control points 404 arecreated by importing combined sagittal image 401 into CATIA Designsoftware, available from Dassault Systemes Americas Corp., and drawingspline curve 402 and control points on eye surface 403. Othercomputer-aided design (“CAD”), computer-aided manufacturing (“CAM”)and/or computer-aided engineering (“CAE”) software known in the art maybe employed.

In a preferred embodiment, each of control points 404 is digitally“attached” to spline curve 402 at anatomical parts of eye surface 403.The density and location of each control points 404 depend on thecurvature of eye surface 403. Any of control points 404 may berepositioned in any direction by selecting and dragging any of controlpoints 404 to alter spline curve 402.

In a preferred embodiment, approximately 30 control points are attachedto spline curve 402. In other embodiments, other numbers of controlpoints are employed.

In a preferred embodiment, haptic section 406 is defined along splinecurve 402 by end point 407 and point 408. Optical section 409 is definedalong spline curve 402 by point 410 and point 411. Haptic section 412 isdefined along spline curve 402 by point 413 and point 414.

Referring to FIG. 5, surface curve 501 is distance 503 from eye surface502 at apex 516. Surface curve 501 has a plurality of control points 504to manipulate the curvature and location of surface curve 501.

In a preferred embodiment, distance 503 is in a range from approximately0.35 mm to approximately 0.5 mm to accommodate for a “settling distance”of the lens on the eye. In this embodiment, the settling distance is ina range of approximately 0.2 mm to 0.25 mm. In other embodiments, otherdistances are employed.

In a preferred embodiment, each of control points 504 is digitally“attached” to surface curve 501 at anatomical parts of eye surface 502.The density and location of each control points 504 depend on thecurvature of eye surface 502. Any of control points 504 may berepositioned in any direction by selecting and dragging any of controlpoints 504 to reposition surface curve 501.

In a preferred embodiment, surface curve 501 is created by selecting anddragging control points 504 to reposition a portion of spline curve 402in FIG. 4 by a predetermined distance from eye surface 502.

Surface curve 501 contacts eye surface 502 at contact points 505 and506. Surface curve 501 has end points 507 and 508. End point 507 isdistance 509 from centerline 510. Contact point 505 is distance 511 fromcenterline 510. Contact point 506 is distance 512 from centerline 510.End point 508 is distance 513 from centerline 510. Haptic section curve514 of surface curve 501 is defined by end point 507 and contact point505. Haptic section curve 515 of surface curve 501 is defined by endpoint 508 and contact point 506. Haptic section curves 514 and 515contact eye surface 502.

In one embodiment, the distances of surface curve 501 are listed inTable 1 below. In other embodiments, other distances are employedaccording to the desired lens design.

TABLE 1 Distance No. Length Distance 503 0.4 mm Distance 509 9.5 mmDistance 513 9.5 mm Distance 511 7.25 mm  Distance 512 7.25 mm 

Referring to FIG. 6, set of surface curves 600 includes surface curves601, 602, 603, 604, 605, and 606. Surface curves 601, 602, 603, 604,605, and 606 are joined at apex 607. Each of surface curves 601, 602,603, 604, 605, and 606 is separated from each other by angle α. Each ofsurface curves 601, 602, 603, 604, 605, and 606 extends along a sagittalplane as shown in FIG. 3A. Surface curve 601 extends along sagittalplane 305. Surface curve 602 extends along sagittal plane 304. Surfacecurve 603 extends along sagittal plane 303. Surface curve 604 extendsalong sagittal plane 302. Surface curve 605 extends along sagittal plane307. Surface curve 606 extends along sagittal plane 306.

Step 204 will be further described with reference to FIGS. 7A, 7B, 7C,7D, 8, and 9.

Referring to FIG. 7A, optical point cloud 700 is imported from aspreadsheet of predetermined point values. Optical point cloud 700 is aset of three-dimensional coordinates. Optical point cloud 700 has set ofback surface points 701 and set of front surface points 702, thickness703, diameter 704, and height 705, each of which may vary according tothe desired lens design. The predetermined point values are a set ofpolar coordinates generated from standard optical lens design methodsknown in the art that depend on the desired diameter, material, focalpower, refractive index of the desired material, sagittal value of thecurve of the desired material, and a minimum thickness of the desiredmaterial, and the general shape of the optical surfaces, i.e.,spherical, aspherical, or toric. The curvature of set of front surfacepoints 702 depends on the curvature of set of back surface points 701.For example, at a given diameter and a given set of back surface pointsthe curve of the front optical surface will generally have a steepercurve as the focal power increases and a flatter curve as the focalpower decreases.

In one embodiment, the predetermined point values of set of back surfacepoints 701 are determined by the method disclosed in U.S. applicationSer. No. 13/277,139, filed on Oct. 19, 2011 and is incorporated hereinby reference.

In a preferred embodiment, set of back surface points 701 is importedfirst and set of front surface points 702 is imported second. In thisembodiment, set of back surface points 701 is separated from opticalpoint cloud 700 by determining a first set of surface coordinates that,when positioned on an eye, are closest to the pupillary center. In thisembodiment, set of front surface points 702 is separated from opticalpoint cloud 700 by determining a second set of surface coordinates that,when positioned on an eye, are furthest from the pupillary center.

Referring to FIG. 7B by way of example, set of back surface points 701is imported and separated from optical point cloud 700. Set of backsurface points 701 has diameter 706 and height 707.

Referring to FIG. 7C by way of example, surface 708 is generated fromset of back surface points 701 by connecting the point values of set ofback surface points 701.

In a preferred embodiment, surface 708 is a best fit non-uniformrational B-spline (“NURBS”) surface. In another embodiment, surface 708is a t-spline surface. In another embodiment, surface 708 is asubdivision surface. Other surface models known in the art may beemployed.

Referring to FIGS. 7D and 7E, corners of surface 708 are trimmed usingtrim tool 709 to create optical surface 710. Optical surface 710 hasdiameter 711 and height 712 that matches diameter 706 and height 707 ofset of back surface points 701, respectively.

Referring to FIG. 8, steps 204 and 205 will be further described.Optical surface 901 has surface edge 916. Optical surface 901 isoverlaid on surface curve 902 and eye surface 903. Surface edge 916 ofoptical surface 901 is aligned with surface curve 902 through controlpoints 920 and 921 by selecting and dragging optical surface 901 toreposition optical surface 901. Surface curve 902 is further alignedwith surface edge 916 of optical surface 901 at control points 920 and921 by selecting and dragging control points 920 and 921 so that surfacecurve 902 is substantially tangential to surface edge 916 at controlpoints 920 and 921. Optical surface 901 is trimmed with trim tool 918 tocreate surface edge 917 and define surface edge 916 from point 920 topoint 921. Surface edge 917 is adjacent eye surface 903 and does notcontact eye surface 903.

Surface curve 902 is trimmed with trim tool 918 by deleting portions ofsurface curve 902 covered by trim tool 918 to create haptic surfacecurves 904 and 915. Haptic surface curve 904 is defined from point 922to point 926. Haptic surface curve 915 is defined from point 927 topoint 931. Haptic surface curves 904 and 915 contact eye surface 903.

The slope of haptic surface curve 904 may be altered using points 922,923, 924, 925, and 926 by selecting and dragging any of points 922, 923,924, 925, and 926 to reposition haptic surface curve 904. The slope ofhaptic surface curve 915 may be altered using points 927, 928, 929, 930,and 931 by selecting and dragging any of points 927, 928, 929, 930, and931 to reposition haptic surface curve 915. Altering the slopes ofhaptic surface curves 904 and 915 provides a better fit of hapticsurface curves 904 and 915 on eye surface 903.

Each of haptic surface curves 905, 906, 907, 908, 909, 910, 911, 912,913, and 914 is created as previously described. Each of haptic surfacecurves 904, 905, 906, 907, 908, 909, 910, 911, 912, 913, 914, and 915extend along a sagittal plane as shown in FIG. 3A. Each of hapticsurface curves 904, 905, 906, 907, 908, 909, 910, 911, 912, 913, 914,and 915 is separated from each other by angle α. Haptic surface curves904 and 915 extend along sagittal plane 302. Haptic surface curves 905and 914 extend along sagittal plane 303. Haptic surface curves 907 and912 extend along sagittal plane 304. Haptic surface curves 909 and 910extend along sagittal plane 305. Haptic surface curves 911 and 908extend along sagittal plane 306. Haptic surface curves 913 and 906extend along sagittal plane 307.

Referring to FIG. 9 step 206 will be further described. Haptic surface1002 is generated to connect haptic surface curves 1003, 1004, 1005,1006, 1007, 1008, 1009, 1010, 1011, and 1012.

In a preferred embodiment, haptic surface 1002 is a best fit NURBSsurface. In another embodiment, haptic surface 1002 is a t-splinesurface. In another embodiment, haptic surface 1002 is a subdivisionsurface. Other surface models known in the art may be employed.

In a preferred embodiment, optical surface 1001 is a best fit NURBSsurface. In another embodiment, optical surface 1001 is a t-splinesurface. In another embodiment, optical surface 1001 is a subdivisionsurface. Other surface models known in the art may be employed.

Referring to FIG. 10, steps 207 and 208 will be described in furtherdetail. Blend surface 1103 is a best fit surface generated to connectoptical surface 1102 with haptic surface 1104. Lens surface 1101includes optical surface 1102, blend surface 1103 attached to opticalsurface 1102, and haptic surface 1104 attached to blend surface 1103.

In a preferred embodiment, blend surface 1103 is a best fit NURBSsurface. In another embodiment, blend surface 1103 is a t-splinesurface. In another embodiment, blend surface 1103 is a subdivisionsurface. Other surface models known in the art may be employed.

Referring to FIG. 11, step 210 will be further described. Each frontsurface curve 1202 is generated adjacent to back lens surface 1201 andextends along a sagittal plane as shown in FIG. 3A. By way of example,front surface curve 1202 extends along sagittal plane 302. Front surfacecurve 1202 is constrained by back lens surface 1201. Front surface curve1202 has haptic surface curves 1217 and 1218. Front surface curve 1202is trimmed as previously described to create haptic surface curves 1217and 1218. Haptic surface curve 1217 is defined from end point 1206 topoint 1210. Haptic surface curve 1218 is defined from point 1212 to endpoint 1214.

Front optical surface 1220 is overlaid onto front surface curve 1202.Edge 1225 of optical surface 1220 is aligned with front surface curve1202 through points 1221, 1222, 1223, 1224, and 1204 by selecting anddragging front optical surface 1220 to align edge 1225 of opticalsurface 1220 with front surface curve 1202 as previously described.Optical surface 1220 is trimmed as previously described to defineoptical surface 1220 from point 1222 to point 1223.

Point 1204 is distance 1205 from back lens surface apex 1203. End point1206 is distance 1207 from center line 1208 and distance 1209 from backlens surface 1201. Point 1210 is distance 1211 from back lens surface1201. Point 1212 is distance 1213 from back lens surface 1201. End point1214 is distance 1215 from center line 1208 and distance 1216 from backlens surface 1201.

Distance 1205 depends on the desired lens design. In a preferredembodiment, distance 1205 is in a range from 0.15 mm to 0.4 mm.

In one embodiment, the distances of front surface curve 1202 are listedin Table 2 below. In other embodiments, other distances are employedaccording to the desired lens design.

TABLE 2 Distance No. Length Distance 1205 0.25 mm Distance 1207  9.3 mmDistance 1209 0.18 mm Distance 1211 0.35 mm Distance 1213 0.35 mmDistance 1215  9.3 mm Distance 1216 0.18 mm

Referring to FIG. 12, lens 1300 includes back lens surface 1301 andfront lens surface 1302 adjacent to back lens surface 1302. Front lenssurface 1302 includes front haptic surface 1303, front blend surface1304 attached to haptic surface 1303, and front optical surface 1305attached to front blend surface 1304. Each of front haptic surface 1303,front blend surface 1304, and front optical section 1305 is generated aspreviously described with respect to the back surface.

In a preferred embodiment, front haptic surface 1303 is a best fit NURBSsurface. In another embodiment, front haptic surface 1303 is a t-splinesurface. In another embodiment, front haptic surface 1303 is asubdivision surface. Other surface models known in the art may beemployed.

In a preferred embodiment, front blend surface 1304 is a best fit NURBSsurface. In another embodiment, front blend surface 1304 is a t-splinesurface. In another embodiment, front blend surface 1304 is asubdivision surface. Other surface models known in the art may beemployed.

In a preferred embodiment, front optical surface 1305 is a best fitNURBS surface. In another embodiment, front optical surface 1305 is at-spline surface. In another embodiment, front optical surface 1305 is asubdivision surface. Other surface models known in the art may beemployed.

Referring to FIG. 13, step 211 will be further described. Point cloud1401 includes front lens point cloud 1402 and back lens point cloud1403. Front lens point cloud 1402 and back lens point cloud 1403 areseparated by thickness 1406. Thickness 1406 varies depending on theshape of back lens point cloud 1403 and the desired lens design. Pointcloud 1401 further includes point density 1404 and separation distance1405. Point cloud 1401 is a collection of points. Each point is athree-dimensional coordinate to model a three-dimensional lens.

In a preferred embodiment, point density 1404 is approximately 0.1 mm.Other densities may be employed.

In a preferred embodiment, separation distance 1405 is approximately 0.3mm. Other distances may be employed.

In one embodiment, thickness 1406 is approximately 0.25 mm at apex 1407.In other embodiments, thickness 1406 varies according the shape of backlens point cloud 1403 and the desired lens design.

Referring to FIG. 14, step 212 will be described in further detail. Lensimage 1500 has front lens surface image 1501, back lens surface image1502, and lens thickness 1503. Lens thickness 1503 varies depending onthe shape of back lens surface image 1502 and the desired lens design.

In one embodiment, lens thickness 1503 is approximately 0.25 mm at apex1504.

It will be appreciated by those skilled in the art that modificationscan be made to the embodiments disclosed and remain within the inventiveconcept. Therefore, this invention is not limited to the specificembodiments disclosed, but is intended to cover changes within the scopeand spirit of the claims.

1. In a system comprising a network, a computer connected to thenetwork, a camera connected to the network, and a lathe connected to thenetwork, the computer programmed to store and execute instructions thatcause the system to perform a method comprising the steps of: capturinga set of sagittal images; creating a set of combined sagittal imagesfrom the set of sagittal images; creating a set of back surface curvesfrom the set of combined sagittal images; generating a back lens surfacefrom the set of back surface curves; creating a set of front surfacecurves from the back lens surface; generating a front lens surface fromthe set of front surface curves; generating a point cloud from the backlens surface and the front lens surface; converting the point cloud to alens image; converting the lens image to a text file; and, cutting alens using the text file.
 2. The method of claim 1, wherein the step ofcreating a set of back surface curves from the set of combined sagittalimages further comprises the steps of: creating a spline curve for eachcombined sagittal image of the set of combined sagittal images to createa set of spline curves; and, converting each spline curve to a backsurface curve to create the set of back surface curves.
 3. The method ofclaim 1, wherein the step of generating a back lens surface from the setof back surface curves further comprises the steps of: generating a backoptical surface; creating a back haptic surface curve for each backsurface curve of the set of back surface curves to create a set of backhaptic surface curves; generating a back haptic surface from the set ofback haptic surface curves; generating a back blend surface; and,combining the back optical surface, the back haptic surface, and theback blend surface to form the back lens surface.
 4. The method of claim3, wherein the step of generating a back optical surface, furthercomprises the steps: receiving a set of back surface points; generatinga back optical surface from the set of back surface points; and,trimming the back optical surface.
 5. The method of claim 3, furthercomprising the step of changing a slope of each back haptic surfacecurve of the set of back haptic surface curves.
 6. The method of claim1, wherein the step of generating a front lens surface from the set offront surface curves, further comprises the steps of: generating a frontoptical surface; creating a front haptic surface curve for each frontsurface curve of the set of front surface curves to create a set offront haptic surface curves; generating a front haptic surface from theset of front haptic surface curves; generating a front blend surface;and, combining the front optical surface, the front haptic surface, andthe front blend surface to form the front lens surface.
 7. The method ofclaim 6, wherein the step of generating a front optical surface, furthercomprises the steps of: receiving a set of front surface points;generating a front optical surface from the set of front surface points;and, trimming the front optical surface.
 8. The method of claim 6,further comprises the step of changing a slope of each front hapticsurface curve of the set of front haptic surface curves.
 9. In a systemcomprising a network, a computer connected to the network, a cameraconnected to the network, and a lathe connected to the network, thecomputer programmed to store and execute instructions that cause thesystem to perform a method comprising the steps of: capturing a set ofsagittal images; creating a set of combined sagittal images from the setof sagittal images; defining a spline curve for each combined sagittalimage of the set of combined set of sagittal images to create a set ofspline curves; creating a set of back surface curves from the set ofspline curves; generating a back optical surface; creating a back hapticsurface curve for each back surface curve to create a set of back hapticsurface curves; generating a back haptic surface from the back hapticsurface curves; generating a back blend surface; connecting the backoptical surface and the back haptic surface with the back blend surfaceto create a back lens surface; creating a set of front surface curvesfrom the back lens surface; generating a front optical surface; creatinga front haptic surface curve for each front surface curve to create aset of front haptic surface curves; creating a front haptic surface fromfront haptic surface curves; generating a front blend surface;connecting the front optical surface and the front haptic surface withthe front blend surface to create a front lens surface; generating apoint cloud from the back lens surface and the front lens surface;converting the point cloud to a lens image; creating a text file fromthe lens image; and, guiding the lathe with the text file to cut a lens.10. The method of claim 9, wherein the step of generating a back opticalsurface, further comprises the steps: receiving a set of back surfacepoints; generating a back optical surface from the set of back surfacepoints; and, trimming the back optical surface.
 11. The method of claim9, wherein the step of generating a front optical surface, furthercomprises the steps: receiving a set of front surface points; generatinga front optical surface from the set of front surface points; and,trimming the front optical surface.
 12. A system for cutting a scleralcontact lens, comprising: a network; a computer, connected to thenetwork; a camera, connected to the network; a lathe, connected to thenetwork; the computer programmed to carry out the steps of: receiving aset of sagittal images; creating a set of combined sagittal images fromthe set of sagittal images; creating a set of back surface curves fromthe set of combined sagittal images; generating a back lens surface fromthe set of back surface curves; creating a set of front surface curvesfrom the back lens surface; generating a front lens surface from the setof front surface curves; generating a point cloud from the back lenssurface and the front lens surface; converting the point cloud to a lensimage; converting the lens image to a text file; and, guiding the latheto cut the scleral contact lens using the text file.
 13. The system ofclaim 12, wherein the computer is further programmed to carry out thesteps of: creating a spline curve for each combined sagittal image ofthe set of combined sagittal images to create a set of spline curves;and, converting each spline curve to a back surface curve to create theset of back surface curves.
 14. The system of claim 12, wherein thecomputer is further programmed to carry out the steps of: generating aback optical surface; creating a back haptic surface curve for each backsurface curve of the set of back surface curves to create a set of backhaptic surface curves; generating a back haptic surface from the set ofback haptic surface curves; generating a back blend surface; and,combining the back optical surface, the back haptic surface, and theback blend surface to form the back lens surface.
 15. The system ofclaim 14, wherein the computer is further programmed to carry out thesteps of: receiving a set of back surface points; generating a backoptical surface from the set of back surface points; and, trimming theback optical surface.
 16. The system of claim 14, wherein the computeris further programmed to carry out the step changing a slope of eachback haptic surface curve of the set of back haptic surface curves. 17.The system of claim 12, wherein the computer is further programmed tocarry out the steps of: generating a front optical surface; creating afront haptic surface curve for each front surface curve of the set offront surface curves to create a set of front haptic surface curves;generating a front haptic surface from the set of front haptic surfacecurves; generating a front blend surface; and, combining the frontoptical surface, the front haptic surface, and the front blend surfaceto form the front lens surface.
 18. The system of claim 17, wherein thecomputer is further programmed to carry out the steps of: receiving aset of front surface points; generating a front optical surface from theset of front surface points; and, trimming the front optical surface.19. The system of claim 17, wherein the computer is further programmedto carry out the step of changing a slope of each front haptic surfacecurve of the set of front haptic surface curves.